This 3 Inch Set Gives You Both Straight And Rounded Calipers To Measure Just About Anything You Need To. Locking Screw Mechanism Assures Accuracy. 1 X Inside, 1 X Outside, And 1 X Divider. Adjusting Screw Is About 2 Inches, And The Knob Is About 1/2 InchTo Make Overall Screw Size To About 1 1/2 Inch.

• You can measure inside, or outside size of an object with this set-Each is 3 inches
• These calipers are made of steel with hardened points for long life
• They are precision ground with threaded spool mechanisms-this set weighs 4.9 ounces
• You can lock your measurement in place with the turn-screw-then measure
• You can measure the distance an item is open, or measure the diameter of something round